Tanning



WILLIAM H. 0oKLEs'r0N, or BoUnN, AND THOMAS BURNELL CAEMICI-IAEL, on WATERLOO, NEAR LIvnRroo ENGL D;

TANNING.

No Drawing.

To all whom it may concern Be it known that we, WILLIAM HENRY OOKLESTON and THOMAS BURNELL CAR- MICHAEL, subjects of the King of Great the object of shortening the period of drying, more particularly in the case of vegetable tanned leather, and this without darkening or streaking the surface. 1

According to the invention the hides or the. like after being-subjected to the tannage are treated with an aqueous solution of pyridine which fixes the tanning agent and permits washing and subsequent rapid drying without liability for the tanning agent to bleed or sweat out and so cause a darkening V orstreaking of the surface.

When a vegetable tanning agent is used the washing is effected in a weak acid solution.

would be varied in accordance to the kind of hides to be treated and the qualitydesired in the resulting product, and in average cases would be about 10 to 25 percent.

Hides after being subjected in the usual manner to, say, vegetable tanning agents, and before oiling are treated with the pyri dine solution in which they are soaked for, say, four to twelve hours; the hides may then be washed withoutloss of the tanning substances; as stated, when a vegetable tanning agent is employed the washing is carried out with a weak acid condition, say a 5% solution. A 5% aqueous solution of oxalic acid forms an excellent-washing solution, butrweak solutions'of other organic acids, such as formic acid, may be employed for washing, and-in some cases inorganic acids, say sulphuric acid may be used for acidifying the washing solution. 7

After treatment with the pyridine the tanning agent in the hides or the like is not solublein the washing solution, so that there r is no loss" of the tanning agent in the wash- The strength of the pyridine solution witnesses: ing The use of the acid washing solution I also has the'e filect of ,brighteninglthef colour Specification of'Let ters Patent, lPatentefl 18, 1922 Application filed January 21, 1922. Serial No; 530,955.

of the resulting leather. The hides are oiled 1n the usual manner after washing. I After washing,'the hides are rapidly dried 1n,'say a hot stove, the product being uniform in colour and there being little risk of the darkening or streaking which results in the ordinary processes, in consequence of the tannlng material coming to the surface, especially when the attempt is made to shorten the periodof drying.

In the case, for example, of alum tannage, the hides after the "alum treatment are transferred to the pyridine solution for a suitable period, usually from fourto twelve hours; this treatment fixes the alum so that the hides may be washed without loss ofalum and without the resulting-hardening of the i leather such as occurs in the ess of alum t'annage. V

*We alsoifind that though the chrome in ordinary proc- "chrome tanning is not-so liable to be washed out as is the case with other tannages, a'better fixing and resulting product is obtained by the pyridine treatment. i

Having now particularly described and ascer'tainedthenature of our said invention, andi-n what manner the same is to be-p erformed, wedeclare that what we claim-is f. i

1. A method of tanning which includes the step of subjecting the material being i tanned to the action of pyridine.

.2. A method of tanning, which includes the step ofsubjecting the material being tanned to the action of an aqueous solution of pyridine and washingwith acid solution.

3..A method of tanning which includes the-stepof subjecting the material being tanned to theaction of a ten per cent solu-' tion of pyridine. 7

theistepofsubjectingthe material being tanned to the actlon of-pyridine, and then'f" "treating the material with oxalic acid. 5; A-method of tanning'which" includes the step of subjecting the material being tanned to the action ofpyridine and then treating the material with 5 per cent oxalic f vacid: *In

' j'uioivms BURNELL cAai liciiatr. j

V KJosnria'EiHmscr, fJ-MARG RITAJONESL- V i V 1 L A method of tanning which includes 

